$ perl -Mstrict -Mwarnings -E '
my %weekly_hash;
my $i = 1;
push @{ $weekly_hash{$i} },"mon","ret","tue","retik","wed","true";
say scalar @{ $weekly_hash{$i} };
'
6

##</code><code>##

$ perl -Mstrict -Mwarnings -E '
my %weekly_hash;
my $i = 1;
push @{ $weekly_hash{$i} },"mon","ret","tue","retik","wed","true", undef;
say scalar @{ $weekly_hash{$i} };
'
7

##</code><code>##

$ perl -Mstrict -Mwarnings -E '
my %weekly_hash;
my $i = 1;
push @{ $weekly_hash{$i} },"mon","ret","tue","retik","wed","true", undef;
say scalar @{[ grep { defined } @{ $weekly_hash{$i} } ]};
'
6